1. Field of the Invention
This invention relates to an adhesive coating machine.
2. Description of the Prior Art
In producing corrugated cardboard boxes, for example, an adhesive such as a hot melt type is applied to the margins for the adhesive of the corrugated cardboard sheet. The conventional adhesive coating machine that has been most widely used has a construction in which the adhesive is pressure-fed into a nozzle by an air pump driven by an air pressure or a gear pump driven by a motor and an object matter to be coated that passes through the nozzle portion is detected by means of a detector such as a photoelectric tube, a limit switch or the like so that an air valve which is interposed between the pump and the nozzle and is driven by the air pressure or an electromagnetic valve is subjected to the ON-OFF control. The adhesive is ejected from the nozzle when the object matter to be coated which is fed into the nozzle portion is detected.
Accordingly, the adhesive coating machine of the kind above-described requires the power for the pump, the detector for the object matter to be coated, the switch valves for the discharge control of the adhesive and a control circuit for these devices and hence, becomes extremely costly.